contestada

A boy rides away from home in an automobile at the rate of 28
km/h and walks back at the rate of 4 km/h. The round trip
bequires 2 hours. How far does he ride?​

Respuesta :

aliciawallace90

Answer:

7 miles

Step-by-step explanation:

Let x be the number  of hours he rides away from home at 28 mph.

Then, since the speed of the automobile is 7 times his walking speed, the number of hours he spends walking is 7x.

Then, the total time, which is 2 hours, is equal to x plus 7x, or 8x.

8x=2-->x=1/4

So the amount of time he spends in the automobile is x=1/4 hour.

The distance he travels in 1/4 hour at 28 mph is 7 miles.

Avg speed of the round trip= 2*28*4/(28+4)= 7 mi/hr

RT=7*2=14 miles

--> 7 miles each way.

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